
def Fun_Fact(x):             #定义阶乘函数，对x求阶乘
    if x==0:
        return 1
    elif x>=1 :
        return x*Fun_Fact(x-1)
    else:
        return False
    
def Fun_Comb (m, n):         #调用阶乘函数，使用题目公式，再设计函数计算组合数\\
    if m>=0 and n>=0:
      return Fun_Fact(n)/(Fun_Fact(m)*Fun_Fact(n-m))
    else:
        return False

 
 
a,b = input().split(',')
if a.isdecimal() and b.isdecimal() and (int(a)<=int(b)):
    Comb_Result = Fun_Comb(int(a), int(b))
    print("result={:.2f}".format(Comb_Result))
else:
    print("Error data,please input again!")

